The effect of different dual tasks conditions on gait kinematics and spatio-temporal walking parameters in older adults

Background: Dual-task (DT) walking has increasingly been investigated over the last decade because of its valuable role as a clinical marker of both cognitive impairment and fall risk in older adults based on cognitive and motor performance (DTEcog, DTEmotor). However, there is still a lack of information on what type of dual task to choose and which is the most adapted to the population of interest. Research question: To evaluate the effect of different dual-tasks (DT3, DT7, FLU, STROOP) on the spatiotemporal and kinematic parameters of hip, knee, and ankle joints. Methods: Thirty-eight older adults were recruited (9 men, 29 women, mean age = 77.5 +/- 6.5 years, mean height = 163.6 +/- 8.6 cm, mean weight = 67.5 +/- 15.3 kg). They performed a single and dual-task walk with the 4 types of tasks during 1 min, equipped with an inertial system. Dual-task effect (DTE) on spatiotemporal and kinematic variables as well as cognitive score and speed were calculated. Results: An alteration in most of the spatiotemporal parameters was observed in each DT condition (p < 0.05), especially in arithmetic tasks (DT3, DT7), while no DT effect was noticed on kinematic parameters (RMSE<3 degrees) except on hip and knee angular velocities (RMSE>15 degrees). Arithmetic tasks seemed to alter more spatiotemporal and kinematic parameters than the verbal fluency or STROOP test. However, DT7 appeared to be too difficult for the population of interest. Significance: Arithmetic tasks seemed to be very pertinent as a clinical dual-task protocol for older adults. The use of an inertial system to retrieve kinematic variables is an improvement in these dual-task protocols.